Orthopedic, orthotic, and prosthetic devices are widely known and employed for attachment to the human body to replace, adjust, or control of movement of various parts of the body. In orthopedic and orthotic appliances designed for attachment to the foot, leg, arm, or hand of the body, a mechanical joint is often employed to pivotally interconnect two members of the appliance to permit and control relative movement of the members and the corresponding parts of the body to which the members are attached. Orthotic appliances generally are composed of members formed of molded rigid plastic, or other material, which are conformed to fit the shape of the body portion to which they are attached.
In one particular appliance, an ankle foot orthosis, a first molded plastic member of the orthosis shaped to conform to the lower ankle and plantar region of the foot is pivotally interconnected to a second molded plastic member shaped to conform to the rear lower leg and calf of the wearer. The two members are interconnected pivotally at their sides adjacent the ankle of the wearer by mechanical joints to provide lateral support to the lower leg, ankle, and foot of human patients who present weak ankle dorsiflexors coupled with swing and stance phase lateral instability of the subtalar joint. The orthosis permits pivotal movement of the foot about the ankle relative to the lower leg during plantarflexion and dorsiflexion of the foot.
One such prior art ankle foot orthosis connecting joint consists of a pair of pivotally interconnected metal disks for respective attachment to leg and foot members of the orthosis. One of the disks is provided with an arcuate slot radially spaced from the pivot point of the disk. A protrusion on the other disk extends into the slot and moves therealong to limit the relative rotation between the disks and the relative pivotal movement of the two members of the orthosis. The orthosis correspondingly limits dorsiflexion and plantarflexion of the foot relative to the lower leg of the wearer.
Connecting joints for orthosis members also have been comprised of a peripherally serrated circular disk which is fixed to one member, and an arm member attached to a second member. The arm member has a serrated opening therein for receipt of the serrated periphery of the disk to intermeshingly fix the angular position of the arm member relative to the disk. Such joint connectors are thus angularly adjustable, but are not known to provide limited pivotal movement of the members to which they are attached.
Ankle foot orthoses have also been constructed with interconnecting joints consisting of a leg bar secured to a leg-supporting member of the orthosis and pivotally attached to a foot plate secured to a foot-supporting member of the orthosis. The leg bar is further provided with a pair of adjusting screws spaced from and located on either side of the pivot point which engage spaced edge portions of the foot plate which also are radially spaced from its pivotal attachment to the leg bar. Adjustment of either or both of the screws varies and limits the degree of pivotal movement of leg and foot members of the orthosis. Such devices are known as double-action orthoses manufactured by U. S. Manufacturing Company and Becker Orthopedic Appliance Company.